Semen quality among Danish and Finnish men attempting to conceive. The Danish First Pregnancy Planner Study Team

Abstract

Objective: To assess differences in semen quality between similar populations from Denmark and Finland. Design: Comparison of semen quality between 221 Finnish men (of whom 115 had no proven fertility) and 411 Danish men with no proven fertility in two follow-up studies among normal couples trying to conceive. Methods: In Finland male partners of couples without experienced infertility attempting to conceive were recruited through advertisements in local newspapers from 1984 to 1986. From 1992 to 1995 Danish men who lived with a partner and who had not attempted to achieve a pregnancy previously were recruited through their union when they discontinued birth control. All semen analyses were performed in accordance with the World Health Organization guidelines. Results: Median sperm concentration, total sperm count and the percentage of morphologically normal spermatozoa were significantly higher among the Finnish men without proven fertility (104.0 million/ml, 304.0 million and 58% respectively) compared with the Danish men (53.0 million/ml, 140.8 million, and 41% respectively). Sperm concentration was 105.7% (95% confidence interval (CI) 58.1%-167.6%) and total sperm count was 127.4% (95% CI 71.4%-201.6%) higher among Finnish men without proven fertility than among Danish men after control for confounders. Conclusions: Some, but hardly all, of the observed difference in semen quality may be explained by differences in recruitment procedures, selection of the men and by methodological differences in semen analysis between the two countries. Also a birth cohort effect may explain some of the differences between countries as the Finnish men were recruited 11 years before the Danish men. Therefore, follow-up studies with identical recruitment and selection of men from the two countries are needed.

The relationship between human semen parameters and environmental exposure to polychlorinated biphenyls and p,p'-DDE.

“…In comparison with two recent wellconducted studies on men attempting to conceive, the percentage of men in our study with sperm concentration below the WHO reference value (18.8%) was higher than in Finnish men (4.5%) but similar to that found in Danish men (17.1% and 18.4%) (Bonde et al 1998;Jensen et al 2000). In a study on an unselected population, 25% of men 18-22 years old who participated in a compulsory examination for military service had sperm concentrations below the reference value (Andersen et al 2000).…”

Second to fourth digit ratio: a predictor of adult testicular volume

“…Furthermore, there is also considerable evidence that the degree of reproductive health among Danish men is lower than that of Finnish males. Finnish males were found to have better semen quality than Danish males (Jensen et al, 2000;Jørgensen et al, 2002). In addition, there is a higher prevalence of cryptorchidism and hypospadias among newborn males in Denmark compared with the ones in Finland (Boisen et al, 2004).…”

The relationship between Y chromosome DNA haplotypes and Y chromosome deletions leading to male infertility

“…Even if not reaching significance (P<0,05), despite the very small sample size, the highest difference between haplogroup distribution in Y-deleted males and in the relevant control population was found among the Danish population. This result is intriguing in light of the fact that the Danish population has one of the lowest mean sperm counts in Europe (Jensen et al 2000).…”